1. Field of the Invention
The present invention concerns fuse cutout assemblies. More particularly, the invention is directed to an improved cutout assembly having means to aid in removal and replacement of a fuse tube.
2. Description of the Prior Art
Fuse cutout assemblies having removable fuse tubes have been in use for many years. The devices are generally characterized by the provision of an insulator mounted on a bracket having spaced contact assemblies. A lower contact assembly has a pair of spaced opposing trunnion sockets formed therein, while an upper contact assembly has a integral latching member, usually spring loaded. A fuseholder of the assembly has a lower end with opposing contact ears or trunnions that are adapted for insertion in journaled relation within the trunnion sockets. The upper end of the fuse tube has a latching contact end shaped for engagement with the upper contact assembly of the bracket. The fuseholder is thus removably positioned both physically and electrically in parallel with the insulator.
Servicing these cutout assemblies, e.g., replacing the fuse, is generally accomplished by engaging the operating end of an extended hook stick within a pull ring provided proximate the upper contact assembly and corresponding latch. The worker then pulls down on the ring disengaging the latch and allowing the fuse tube to be accessed. Once the service/repairs are complete, the worker again engages the hook stick with the ring and rotates the fuseholder upwardly until the latch is engaged. A common problem encountered by utility company workers when servicing these cutout assemblies is that the fuse tube and its switch contact assemblies become disengaged from the bracket and fall to the ground putting the workers and equipment at risk. When the weather is inclement, as is typically the case, the risk of the fuse tube falling is particularly great. Also, servicing must be done at night or when visibility is otherwise low, causing great difficulty to the worker attempting to engage a relatively small ring with a hook stick from as much as 40 feet away. Regardless of how large the ring is made, the worker must still visually verify engagement of the hook stick therewith, and this can be an extremely time consuming operation. Furthermore, when replacing the fuseholder of the assembly, visual alignment of the fuseholder to ensure that the trunnions are properly positioned relative to the trunnion sockets is difficult, and improper alignment virtually guarantees that the fuseholder will fall, with the attendant risk of injury. Accordingly, many modifications have been made to the “standard” cutout assembly to reduce the risk of the fuseholder falling, both when engaging and disengaging the fuse tube. The modifications are typically fairly complex and are of limited effectiveness. Furthermore, most modifications that are considered “safety features” are often bypassed as they tend to make the service even more tedious, while only providing a limited safety factor. Finally, some manufacturers propose cutout assemblies radically different from standard assemblies, which have the drawback that technicians are totally unfamiliar with them and are unlikely to be proficient when servicing them.
U.S. Pat. No. 5,670,927 issued to Fennell discloses a fuse holder with built in safety features. In lieu of a ring, the device has a slot within which the operation end of the hook stick may be placed to effect removal of the fuse tube. The problem with the Fennell device is that the slot is fashioned on the lower end of the fuse tube limiting the amount of torque that can be generated. Also, Fennell contemplates doing away with the ring entirely, not merely modifying it.
U.S. Pat. No. 2,331,847 issued to Schultz discloses a fuse device having a pull ring with an enlarged, substantially right triangular shape. Also, Schultz discloses the provision of a pair of annular flanges to assist in positioning the trunnions within the trunnion sockets. Again, Schultz contemplates replacing and not modifying the traditional cutout assembly. Also, the flanges add additional bulk to the lower contact end of the assembly, possibly increasing the difficulty of replacing the fuse.
The present invention is directed to a fuse cutout assembly having enhanced safety features to aid in both removal and replacement of fuse tubes. The inventive assembly can be produced by making modifications to standard fuse cutout assemblies. The modifications include lengthening the trunnions of the lower contact assembly and adding reflectors as a further visual aid for positioning the lower contact portion of the fuse tube within the trunnion sockets. Additionally, a molded plastic guide placed proximate the lower contact area of the fuseholder of the cutout promotes “self guiding” of the fuseholder during replacement. Also, the pull ring is modified by the addition of protruding arcuate sections extending from a standard pull ring, the sections allowing the technician to engage the pull down ring without aiming the hook stick through the ring. Additional reflectors are strategically placed to facilitate replacement of the fuseholder.